Boiler furnace



' E. A. PACKARD BOILER` FURNACE Filed N'ov. 5, 1925 2 Sheets-Sheet lullllmrl f1/wanton E. A. PACKARD BOILER FURNAGE Nov. 2o, 192s.

Filed Nov. 5, 1925 2 sheets-sheet 2 Patented Nov. 20, 1928.,

UNITED STATES NT oFFicE.. i

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EDWIN A. PACKARDQOF YONKERS, NEW YORK, ASSIGNOR TO INTERNATIONAL COM-BUSTION ENGINEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION FDELAWARE.

BOILER FURNACE.

Application led November 5, 1925.

This invention relates to boiler-furnaces and it is particularly usefulwhere the fuel is to be burned in finely divided form 1n suspension, asfor example, in the form of powderedcoal.

It has recently been proposed 1n pulverized coal burning installationsto at one and the same time greatly decrease the size of the boiler aswell as of the whole installation and to obtain the same or greatersteaming capacity than heretofore obtained in what would becorresponding standard constructions.

In accordance with such arrangement, it

has been proposed to practically deinethe combustion space with thetubes of the boiler,

i. e. to provide a furnace shaped boiler within which the fuel is burnedso that the tubes of the boiler are subjected to radiant heat,

the amount of work done by convection being relatively small'. The tubesdeiining the upright sides of the combustion space, according to suchproposal, have been provided with longitudinally extending fins so as toprovide in eii'ect continuous water walls.

In such arrangement, however, the width of the ns must be comparativelynarrow in order to prevent the edges of the fins from burning oil' andconsequently the tubes must be relatively closely space altho they aremore widely spaced than if no lins were employed.

According to one phase of my invention, I propose to obtain theadvantages -of the water wall construction described, while at the sametime making it possible to decrease the number of tubes and to increasethe width of the fins employed.

Another of the advantages of the general construction previouslydescribed is that the extensive and heavy refractory side walls areeliminated for the reason that the water walls themselves define theboundaries of the combustion space, comparatively light sheathings toprevent radiation to the eX- terior being substantially all that isrequired in place of the usual refractory walls.

As to this phase of my invention I propose to obtain these advantages byemployling a novel arrangement of tubes to be more particularlyhereinafter described.

The foregoing, together with such other objects as may hereinafterappear, or are incident to my invention, I obtain by means Serial No.66,929.

of a construction illustrated in preferred form in the accompanyingdrawings wherein,

Fig. 1 is a vertical section thru a boilerfurnace installation embodyingIny invention;

Fig. 2 is a diagrammaticview illustrating a modiiicationof my invention;

Fig. 3 is a fragmentary sectional view illustrating a detail of thearrangement of Fig. 2, and i Figs. 4 and 5 are sectional viewsillustrating a different manner of ring the fuel from that shown in Fig.1, Fig. 4 being a section taken on the line l4 4 of Fig. 5.

Referring now to Fig. 1, the reference character A denotes thecombustion space of the'boiler-furnace. Four upright water walls definethe four upright sides of the furnace, such Vwalls being composed oftubes 7 provided with the longitudinally extending fins 8 previouslydescribed. The tubes 7 constituting the front water wall have their endsconnected in the upper drum 9 and the lower drum 10, and the tubes 7 ofthe rear water wall have their ends connected to the drums 11 and 12respectively. The drum 12 lies above the level of the drum 10 and thedrum 11 lies above the level of the drum 9. The ktubes 7 of the sidewater walls have their upper ends connected into the header 13 and theirlower ends connected into the header 14, the headers 13 connecting withthe drum 11 and headers 14 connecting with the drum 10. Suciently largedowncomer tubes 15 connect the drum 11 with the drum 10. The top of thecombustion space is defined by a water wall c composed of tubes 16provided with fins 17 as above. A number of inclined tubes 18 extendingfrom the drum 10 to the drum 12, define the bottom of the combustionspace, such tubes being spaced sufficiently far apart to permit therefuse to freely gravitate therefrom into the' ash space 19 therebelow.

The upright water walls described are closed by a sheathing 20, and asimilar sheathing 21 is carried by the tubes 16. The ash hopper 19closes the bottom of the furnace, the ofl'take 21 for the waste gases ofcombustion leading from the space dened by the hopper.

The tubes 7 and the tubes 16 are relatively widely spaced apart and thefins carried thereby are correspondingly wide (see for example Fig. 4).ln the absence of provision to the contrary the edges of the fins wouldbe burned off because the width of the fins is preferably so great thatheat cannot be conducted into the tubes from the edges with sutiieientrapidity to prevent such edges from burning. I, therefore, provide infront of each of the side water walls and below the top water wall,boiler tubes which are staggered with reference to the tubesconstituting the side and the top water Walls so as to come opposite theedges of adjacent tins, thereby shading the tins and shielding them fromthe direct radiant heat. The shading tubes for the upright walls areindicated at 22. The shading tubes for the front and rear water wallsare connected respectively to the drums 9 and 1.0 and the drums 11 andl2, While the shading tubes for the side water walls are connected tothe headers 13 and 14. The shading tubes 23 for the upper water wall areconnected to the drums l1 and 9.

It will be seen from the foregoing that circulation is established fromthe drum 1l to the drum l0 and thence upwardly thru all of the tubesdescribed back thru the drum ll. The tubes constituting the water wallsand the shading tubes as well are all subject to radiant heat and,therefore, heat is transmitted at a very high rate and a very smallboiler can be employed to produce a very large quantity of steam. Byvirtue of the employnient of the shaded tubes the water wall tubes canbe Widely spaced apart and large fins may be employed Withoutencountering the difficulty of burning oil' and thus a practicallycontinuous metallic Wall can be employed. Also, if desired, the fins maybe dispensed with by virtue of the employment of the shading tubes,because the shading tubes'in such case Would shade that portion of thesheathing not directly covered by the tubes of the Water walls.

Steam from the drum 1l is led thru the super-heater 24 located in thebottom of the olftake 21 and the air heater B is located in suchotl'take immediately above the super* heater elements.

The gases leaving the combustion space defined by the radiant heat tubesis at a very high temperature, `much higher than usual, in order that ahigh degree of preheated air may be obtained in the air preheater. Thishighly heated air is used for combustion and is taken from the heater bythe ducts 25 leading to the burners 26 located at the four corners ofthe combustion space, preferably near the upper portion thereof. Theseburners discharge into the corners in a manner to producevortical'mixture and combustion, the combustion being intense andturbulent, whereby a high llame temperature and short length of flametravel is obtained.

Referringnow to Figs. 2 and 3, I have being connected to the drum 3l bydowncomers 32, While the upper portion of the next header is connectedby upcomers itil to the drum 34, downcomers connecting the lower-most ofthe upper part of headers to the drum 31 and upcomcrs 3G connecting theupper of the two higher headers to the drum 34, Tubes 37 connect the twodrums 3l and 34. It is obvious that the ar rangement of Figs. 2 and 3may be employed with fuels otherv than pulverized coal.

Referring now to the arrangement of Figs. 4 and 5, the burners88, inthis rase, extend downwardly thru an arch Bt) supported on tubes 4()constituting an outer water Wall. Certain of such tubes are formed so asto shade the edges oi the burner casting, the tins being interrupted forthis purpose. The object of so shading the. burner casting is to preventburning thereof, particularly where intense turbulent combustion isemployed.

What I claim is:

l. In a boiler furnace, water walls delining combustion space andcomprising tubes having longitudinal fins of such width that in normaloperation of the furnace a portion thereof would burn off and meansshading said tins to prevent such burning off.

2. In a boiler furnace, Water walls delining combustion space andcomprising tubes having longitudinal fins of such Width that in normaloperation of the furnace a por- Ition thereof would burn off and othertubes also subject to radiant heat spafjed inwardly from said firsttubes and coming opposite the fins to prevent such burning ott'.

3. In a boiler furnace, water walls detining combustion space andcomprising tubes having longitudinal tins of such width that. in normaloperation of the furnace the heat absorbed by said tins could not beconducted to the said tubes rapidly enough to prevent burning off ofsaid fins, and other tubes also subject to radiant heat spaced inwardlyfrom said first tubes and coming oppositie the said tins to prevent suchburning oil'.

In testimony whereof, I have hereunto signed myname.

EDWIN A. PACKARD.

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